The invention described in this specification is primarily intended to be utilized in conjection with the production of tubes to be utilized for water distribution purposes, but which are also capable of being used for other purposes. It is also capable of being used with other flexible structures or members. Such tubes are commonly utilized as irrigation conduits. They are formed so as to include periodically spaced external holes used to distribute water from their interiors to their exteriors at various spaced points along their lengths.
The simplest form of such a tube consists of an elongated tubular member, normally a member of circular cross-sectional configuration, having comparatively fine holes spaced along its length. It has been discovered that tubes having an internal wall dividing them into two internal sections and having periodically spaced holes in this internal wall are more desirable than simple tubes having undivided interiors for water distribution purposes because with such internally divided tubes it is possible to obtain a pressure step-down effect tending to restrict the amounts of water emitted from the external holes employed.
With both of these types of tubular irrigation conduits a problem has been encountered in creating the holes used so that these holes are of a carefully controlled dimension so that the amounts of water emitted through them and/or passing through them will be regulated in order to achieve substantially uniform water distribution along the length of a tube and/or in order to achieve controlled water distribution along the length of a tube. In connection with this, it will be realized that such controlled water distribution is necessary for efficient, economic irrigation without the waste of water.
This problem is considered to be particularly severe because of the fact that strength material thickness considerations have made it desirable to utilize seamless tubes for water or similar distribution purposes. Such seamless tubes are comparatively hard to process utilizing conventional hole producing methods so that holes are created in them which are extremely uniform in character and/or are of a carefully controlled character, and which are of such a nature that their interiors do not contain internal fragments or projections which might interfere with a controlled or metered distribution of water.